1. Field of the Invention
The present invention relates in general to the field of information handling system power subsystems, and more particularly to a system and method for managing power consumption of an information handling system.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
As information handling system components have improved performance over the past several years, power consumed by components within information handling systems has also tended to increase. Increased power consumption by components has led to a number of improvements that reduce overall power consumption by information handling systems. For example, information handling system manufacturers have adopted an ACPI standard having reduced power states to help reduce information handling system power consumption when an information handling system is not actively in use. The reduced power states are designated as S0 through S5, with S0 representing a fully on state and S5 representing a fully off state. Intermediate reduced power states S1 through S4 have at least some components of the information handling system powered down to reduce power consumption. For example, the S3 state suspends operating information in RAM and powers down other components. The S4 state suspends operating information to permanent storage, such as a hard disk drive, and powers down all components.
In particular, power consumption presents a concern for portable information handling systems because portable systems sometimes run on an internal battery having a limited charge life. Portable information handling systems typically use an external AC-to-DC power adapter that converts AC power provided from an external power source into DC power for use by the portable information handling system. Desktop information handling systems also use an AC-to-DC converter to convert external AC power into DC power for use by internal components, however, the AC-to-DC converter is generally incorporated into the housing of the information handling system. Usually, the AC-to-DC converter provides a set voltage, such as approximately 19 Volts DC, at a power connector located at the housing of the information handling system and then an internal power subsystem applies the set voltage at different levels of Voltage to a number of different power rails for powering different components. Energy Star standards specify low power consumption levels for information handling systems in reduced power states and the off state so that the power consumed by an external AC-to-DC adapter must remain minimal in the reduced power and off states in order to meet the Energy Star standards. These reduced power consumption levels have become more difficult to meet as the amount of power required from AC-to-DC adapters has increased. One solution to reduce power consumption is to add a load switch to reduce leakage current, however, this solution complicates power subsystem design, especially where power subsystem DC-to-DC converters have to provide DC power levels with and without engagement of the load switch.